Method and system for non-invasive optical blood glucose detection utilizing spectral data analysis

• US 9,579,049 B2
• Filed: 09/11/2012
• Issued: 02/28/2017
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: St. Louis Medical Devices, Inc.
• Original Assignee: St. Louis Medical Devices, Inc.
• Inventors: Xu, Zhi
• Primary Examiner(s): Stout, Michael C
• Application Number:
  US13/610,140
• Publication Number:
  US 20130006070A1
• Time in Patent Office: 1,631 Days
• Field of Search: 600/309, 600/310, 600/316, 600/322, 600/323, 600/335, 600/336
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 2576/00 Medical imaging apparatus involving image processing or analysis A61B1/00009, A61B6/52 and A61B8/52 take precedence; image processing per se G06T; details of algorithms for analysing medical images G06T7/0012
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass

Abstract

Systems and methods are disclosed for non-invasively measuring blood glucose levels in a biological sample based on spectral data. This includes utilizing at least one light source configured to strike a target area of a sample, utilizing at least one light filter positioned to receive light transmitted through the target area from the at least one light source, utilizing at least one light detector positioned to receive light from the at least one light source and filtered by the at least one light filter, and to generate an output signal, having a time dependent current, which is indicative of the power of light detected, receiving the output signal from the at least one light detector with a processor and based on the received output signal, calculating the attenuance attributable to blood in a sample with a signal-to-noise ratio of at least 20-to-1; and determining a blood glucose level.

Claims

1. A system for detecting glucose in a biological sample, comprising:

at least one light source configured to generate one or more light beams having a wavelength in a range between 800 nm and 1600 nm to strike a target area of a biological sample;

at least one photocurrent signal generating light detector positioned to receive light from the at least one light source and to generate an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected;

wherein the time dependent output current is a function of a baseline current, a noise current and a time dependent cyclic current corresponding to a heartbeat; and

a light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample and configured to receive the output photocurrent signal from the at least one photocurrent signal generating light detector and based on the received output photocurrent signal, calculate the attenuance attributable to blood in the biological sample present in the target area with a signal-to-noise ratio of at least 20-to-1, and based on the calculated attenuance, determine a blood glucose level associated with the biological sample present in the target area; and

wherein the calculated attenuance is based on an equation for improving a signal-to-noise ratio having at least in part on a standard deviation of a logarithm of the time dependent output current generated by the power of light from the same target area of the biological sample, wherein the equation comprises

2. A system for detecting glucose in a biological sample, comprising

at least one light source configured to generate one or more light beams having a wavelength in a range between 800 nm and 1600 nm to strike a target area of a biological sample;

at least one photocurrent signal generating light detector positioned to receive light from the at least one light source and to generate an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected;

wherein the time dependent output current is a function of a baseline current, a noise current and a time dependent cyclic current corresponding to a heartbeat; and

a light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample and configured to receive the output photocurrent signal from the at least one photocurrent signal generating light detector and based on the received photocurrent output signal, calculate attenuance attributable to blood in the biological sample present in the target area with a signal-to-noise ratio of at least 20-to-1, and based on the calculated attenuance, determine a blood glucose level associated with the biological sample present in the target area; and

wherein the calculated attenuance is based on an equation for noise reduction having at least in part on an approximation of a standard deviation of a logarithm of the time dependent output current generated by the power of light from the same target area of the biological sample, wherein the equation comprises

3. A system for detecting glucose in a biological sample, comprising:

at least one light source configured to generate one or more light beams having a wavelength in a range between 800 nm and 1600 nm to strike a target area of a biological sample;

at least one photocurrent signal generating light detector positioned to receive light from the at least one light source and to generate an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected;

wherein the time dependent output current is a function of a baseline current, a noise current and a time dependent cyclic current corresponding to a heartbeat; and

a light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample and configured to receive the output photocurrent signal from the at least one photocurrent signal generating light detector and based on the received output photocurrent signal, calculate attenuance attributable to blood in the biological sample present in the target area with a signal-to-noise ratio of at least 20-to-1, and based on the calculated attenuance, determine a blood glucose level associated with the biological sample present in the target area; and

wherein the light absorbance change determining algorithm implemented processor is configured to calculate a peak-to-valley height of the change in light absorption due to blood in the biological sample in relationship to time, which is a function of a standard deviation of a logarithm of the time dependent output current divided by a proportionality constant;

4. A method for detecting glucose in a biological sample, comprising:

utilizing at least one light source configured to generate one or more light beams having a wavelength in a range between 800 nm and 1600 nm to strike a target area of a biological sample;

utilizing at least one light photocurrent signal generating detector positioned to receive light from the at least one light source and to generate an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected;

receiving the output photocurrent signal from the at least one photocurrent signal generating light detector with a light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample based on the received output photocurrent signal;

calculating the attenuance attributable to blood in the biological sample present in the target area with a signal-to-noise ratio of at least 20-to-1;

determining a blood glucose level associated with the biological sample present in the target area based on the calculated attenuance with the light absorbance change determining algorithm implemented processor; and

wherein the step of calculating the attenuance attributable to blood in the biological sample present in the target area is based on an equation for improving a signal-to-noise ratio having at least in part on a standard deviation of a logarithm of the time dependent output current generated by the light power from the same target area of the biological sample, wherein the equation comprises

5. A method for detecting glucose in a biological sample, comprising:

utilizing at least one light source configured to generate one or more light beams having a wavelength in a range between 800 nm and 1600 nm to strike a target area of a biological sample;

utilizing at least one photocurrent signal generating light detector positioned to receive light from the at least one light source and to generate an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected;

receiving the output photocurrent signal from the at least one photocurrent signal generating light detector with a light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample based on the received output photocurrent signal;

calculating the attenuance attributable to blood in a biological sample present in the target area with a signal-to-noise ratio of at least 20-to-1 utilizing a peak-to-valley height of the change in light absorption due to blood in the biological sample in relationship to time with the processor, which is a function of a standard deviation of a logarithm of the time dependent output current divided by a proportionality constant;

6. A method for detecting glucose in a biological sample, comprising:

utilizing at least one light source configured to generate one or more light beams having a wavelength in a range between 800 nm and 1600 nm to strike a target area of a biological sample;

utilizing at least one photocurrent signal generating light detector positioned to receive light from the at least one light source and to generate an output photocurrent signal, having a time dependent current, which is indicative of the power of light detected;

receiving the output photocurrent signal from the at least one photocurrent signal generating light detector with a light absorbance change determining algorithm implemented processor programmed to calculate a change in a light absorption caused by blood in the biological sample based on the received output photocurrent signal;

calculating the attenuance attributable to blood in the biological sample present in the target area with a signal-to-noise ratio of at least 20-to-1;

determining a blood glucose level associated with the biological sample present in the target area based on the calculated attenuance with the light absorbance change determining algorithm implemented processor; and

wherein the step of calculating the attenuance attributable to blood in the biological sample present in the target area is based on an equation for noise reduction having at least in part on an approximation of a standard deviation of a logarithm of the time dependent output current generated by the light power from the same target area of the biological sample, wherein the equation comprises